A quotation by John William Strutt
Some proofs command assent. Others woo and charm the intellect. They evoke delight and an overpowering desire to say, "Amen, Amen".
Quoted in H E Hunter The Divine Proportion (New York 1970)
Examples ... which might be multiplied ad libitum, show how difficult it often is for an experimenter to interpret his results without the aid of mathematics.
Quoted in E T Bell Men of Mathematics